Flowserve NMD User Manual

Page 24

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Page 24 of 40

If a check shows a bad running of the

motor pump unit, the user must:


Refer to the "fault finding chart" chapter 7

of this leaflet to apply the recommended

b) Ensure that your equipment corresponds to the

arrangements of this leaflet.

c) Contact FLOWSERVE after-sales Department if

the problem persists.

6.2.4 Mechanical seals
The current maintenance is limited to seal control. It
is necessary to detect any small leakage which
announces the beginning of the deterioration of
friction faces or secondary seal elements (rings,
bellows, synthetic membranes). It is advisable to
stop the pump as soon as possible. Have an
approved seal vendor replace or repair the seal.

6.2.5 Gland packing Pump fitted with a packed gland
A well run in and correctly adjusted packing gland
requires little maintenance.
If, after some time, the leakage becomes too great,
the gland should be tightened again in order to
return these to a normal level.

If re-tightening is not possible, new packing must be
installed Gland packing inspection and removal
a) Remove the shield guards
b) Slide back the gland
c) Remove the packing rings with an extractor

designed for this purpose (including the lantern
ring if it exists; note its position and its direction
of rotation).

d) Inspect the state of the sleeve surface; the

presence of many marked grooves will indicate
that it must be replaced.

e) Carefully clean the different pieces of the

packing gland. Gland packing fitting
If the packing is supplied as cord the packing must
be cut so that the external diameter is lightly
tightened and there is an initial gap between the
sleeve and the packing ring.

For that purpose, wind the packing helically around
the shaft sleeve or a chuck of the same diameter.
(Take precautions to avoid damaging sleeve)

Example of straight cut

Example of bevel cut

Ensure a tightening on the stuffing

box housing and not on the sleeve.


Follow the instructions:
a) Assemble of the packing in S.
b) Stagger by about 90° between two rings.
c) Assemble packing after packing.

After setting the last packing ring, secure the
packing with the gland and tighten the nut by hand.

After tightening, the shaft should turn by hand as
easily as before the setting of the packing.

This manual is related to the following products: